26 DESCRIPTION OF PLATES. Plate IV. Blattella germanica.Fig. 109. Similar stage to figs. 107 and 108; chromosomes U-shaped and not longi¬ tudinally split; two centrosomes present (c). no. Longitudinally split chromosomes.111-113. Various stages in formation of cross-shaped tetrads.114-117. Bent rods, U-shapes, split rings, pairs of rods, and rod-shaped tetrads (116), which are equivalent to the crosses of figs. 112-113.118-122. Metaphase of first maturation division, showing the element x in various positions.123-127. First maturation spindle in metaphase. 128. Same in anaphase.129-132. Late anaphase, showing element .*¦ double in 129, and a lagging tetrad in 130. 133. Telophase, with the element x in one daughter cell.134-136. Prophase of second maturation mitosis, showing dyads and element x.